The present invention relates to log shaping machines for cutting logs to a desired diameter.
Such prior machines for reducing the size of overwide parts of logs to a desired diameter have employed a cutting ring rotatably supported on a machine frame so that is is centered on a line along which the log is moved. Thus, the diameter to which the log parts are cut down on their way through the machine to the next wood processing machines is dependent on the diameter of the cutting ring.
In many cases the diameter of the cutting ring may be changed in known machines by adjustment of the positions of the wood cutting tools in their supports or changing over the tools so that the upper diameter limit of a log coming from the machine may be changed. In this case it is not possible for logs to be processed if there is a change in the upper diameter limit from log to log, without stopping the machine and changing the tool. In fact, the logs have to be sorted before cutting into different diameter groups and the tools can be changed after completing the shaping of one group of logs. The adjustment or exchanging of the tools is not readily undertaken and is a time consuming operation.
Because the diameters of the individual logs may be greatly different even in a sorted group, it is frequently likely for logs with a generally small average diameter, but with strong root outgrowths at the lower end to go through the known machine without such outgrowths being cut back, or only being cut back to a small degree. Such root outgrowths at the "lower" end of the log will then be a cause of trouble in later processing machines, for example in a gang mill, because they are cut away as wedges which in the automatic separating systems for turning out irregular wood or the like are not securily sensed and automatically cleared and may even frequently be the cause of damage to such separating systems.
Furthermore apparatus has been designed in the prior art which is different than the apparatus of the present invention in that a rotating support having the same function as the cutting ring has a number of levers, which when changed in angle in relation to the support in operation of the apparatus, may be placed at different distances from the centerline along which the log is moved, each lever at this end having a rotating cutting head which is moved along a line round the log for cutting the same, the cutting head having its own motor, which is fixed to the other end of the lever. This apparatus is very complex in design and trouble conditions are very likely because of this. In their general design such cutting down systems are generally like debarking machines, but whereas in debarking machines the levers have fixed tools and only have to be pushed elastically towards the line along which the log is moved, in the case of the reducing machines in question the levers have to be able to undergo adjustment into different, exact positions, the same for each lever and the levers have to be locked exactly in such positions. Furthermore it is necessary for the motors turning with the support to be supplied with power. Such a system may only be produced, at least in theory, with a very complex design.